Bystander, Mostly
by waffrus
Summary: How Jack accidentally gives Elsa her powers and the aftermath.
1. Chapter 1

Jack usually forgot about Arendelle.

It was a small kingdom, almost quietly hidden by sea and snow-covered mountains. The sea winds drew in the nearby frost, and he never had to worry about the winters there. Instead he preferred the larger bustling places where he could pretend everyone was too preoccupied with their own lives to see him. And then gleefully disrupt their daily routines with a well-placed snowball. Weselton, for instance, was full of interesting and large crowds of people, though perhaps prone to odd theatrics.

Still, he decided to make his rounds there.

He started in the nearby woods – _there was always something about the woods_ – with a little frost here and there, ice in the water, brisk in the air.

Then he saw her.

Or rather, he thought she saw him.

"Is… Is anyone there?" A woman with labored breath called out, and as he drew nearer, he saw the pained expression on her face. And the swollen belly.

Shit.

What the hell was a pregnant woman doing out in the woods?

Almost as if she could hear his thoughts, the woman murmured to herself, "It's okay, baby… We'll get home soon… And maybe we'll take a walk around here _after_ – when you're older…" She bit back a whimper and stroked her hands across her stomach in soothing motions. "It's getting colder, isn't it…?"

Double shit.

He had already started the beginnings of winter. They had maybe a few hours before snow would start drifting down. For lack of anything else, he sat down next to her with a plop. At the very least, he could keep her company, even if she wasn't aware of it. He considered going to look for help, but he wasn't familiar with the area. He hardly needed to retrace his steps as a drifting spirit – _or whatever the hell he was_ – and the cold was pretty good about spreading where he needed it to.

And it wasn't as though he could tell anyone about her.

She gave a pained gasp and drew into herself. Out of reflex, he tried to cover her hand with his own – _stupid, stupid, it wasn't like it_ _wouldn't just phase through_ –

It worked.

For a brief, tantalizing moment, he felt warmth.

He snapped back with stunned eyes as the woman gave another gasp, this time a mixture of surprise and relief. After a few long moments, she cautiously stood up – he wished he could help her – and stroked her belly once more. "Elsa… Let's get home now, okay…?"

Jack remained on the ground, watching the woman walk away. He had felt – he wasn't sure anymore. The memory of it was fading. But he remembered what he saw. A pattern of frost – if it had been frost, it gleamed too bright to be made of ice and snow – that disappeared where the lady's hand had been.

Over her unborn child.

Triple shit.

What had he done?

* * *

He didn't go back for several years.

When he finally visited that small kingdom once more, he drifted in without bringing the winter. Not just yet, anyways. He searched for that woman, murmuring wishes to the man on the moon. Please let her be okay, _please please please_

He found her in the castle. Of course. She had to be the queen of all people.

With an apologetic look that she couldn't see, he trailed after the woman. She treated her servants kindly, kissed her husband, and all in all, seemed to be a rather nice person for a monarch. And then she was accosted by a tumbling ball of energy and red braids.

"Mommy! I want to go outside, can I go outside? Please, please, please!"

Kneeling down, she greeted her daughter with an indulgent smile. "Of course, dear. But stay in the courtyard. It'll be dark soon, and it's getting colder."

Jack let out a breath of air that he hadn't realized he had been holding in. The queen was fine. The kid was all right. He thought maybe she would be a little older by now, but the years tended to meld together, so he brushed the thought away. She was fine. He hadn't done anything. Hell, he could go back to starting snow fights if there were more kids around the place.

"Anna, don't forget to go with your sister," the queen said as her daughter ran off with a happy squeal.

Oh good, there was another-

"Elsa, let's go make a snowman!" the little girl bellowed as she ran down the hall.

…Elsa?

_Shit_. He remembered that name. With a renewed coil in his gut, he followed the energetic girl as she scrambled to find Elsa.

It didn't take long.

And then he wasn't sure he could breath.

_Her hair_. It looked almost, _almost_ like his. For a moment, he thought her head was full of silver, but as the pair of girls ran past, he saw the pale yellow. Parents with dark locks. A sister with ginger hair. He didn't know much about human genetics, but that was a bit of a puzzle. Unless you throw some magic frost into the mix.

Shit shit shit.

It got worse.

With tiny hands, Elsa drew together a ball of frost, letting loose a landscape of snow to an adoring sister. It was cute, really. They made a snowman and played and made an actual snow _castle_ and-

Well, Arendelle certainly didn't need his services anymore, he thought weakly.

Think.

_Think, dammit_.

He squinted at the pair, trying to untangle his thoughts. A girl with your powers and hair that gleamed like snow – in comparison to her family at least. Had he created some sort of… protégé? An apprentice of sorts? Man on the moon, is that what happened to him?

He felt sick.

And worst of all, she still couldn't even see him.

He left.

* * *

He visited, at first.

The carefree sisters that once played were now separated. He had a feeling it was his fault, his powers that led to this. He tried to leave little gifts. Beautiful designs of frost, miniature snowmen and houses, something to make her smile.

They only upset her, and she wailed to her parents that they couldn't control her powers.

He was right.

One night, with the best of his efforts, he tried to take it away, whatever cursed gift he had given her so many years ago. Her powers lashed out at him, even as she slumbered, and Elsa woke up in a room full of protective frost.

The next morning her father gave her gloves, and he left once more.

* * *

Years later, Jack found another castle. This time, one of gleaming ice and hidden in the mountains. No bright-eyed sister with red hair to be seen. Elsa curled up against the wall, murmuring as if in pain, almost like her mother all those years ago. "Control it, you have to control it, you have to, you have to, please…"

The ice cracked, splintering into something menacing as Elsa grew more distressed.

…This was his fault, wasn't it?

Just as he did before, he sat down next to the woman. She looked a little older than him now. Beautiful though. Her mother had been pretty, too.

"I'm sorry, Elsa."

But she didn't hear him.

* * *

Shit.

_Shit shit shit_.

They almost killed her! _What the hell_? They called her queen, and they almost _killed her_. And now they locked her up, like some sort of monster.

Elsa stared at her shackles, and in frustration, he sent a spark of frost to them. Metal could only take so much cold. But a key would better, he seethed. Do all I can, he mimicked with distain. Who the hell was that guy anyways? And why wasn't he looking for Anna if she was missing? He didn't remember a brother in the family – was it a lover then?

Do all I can, his ass.

His only comfort was the cracking metal.

* * *

In the end, there wasn't much he could do.

Fighting fire with fire - or rather frost with frost - would have been pretty futile. At best, he was able to contain the storm within the general area – no need for a world-wide ice age. The dash of frost to a life-not-yet-begun had certainly grown, he thought with a humorless smile. Aside from her decidedly human nature, she would probably end up stronger than he was.

That same powerful woman sobbed for her lost sister, and his heart clenched.

Still, it turned out all right. In the end.

His eyes grow soft as the two sisters embraced, remembering the pair of little girls that once played in the snow. What was it that they said? Act of true love. Magic of love? It was as corny as it was heartwarming. With a sigh, he watched with envy as Elsa and her loved ones prepared for their happy ending.

There was a moment of devious glee towards Hans, who was mysteriously pelted with snowballs. Inside his cell. At sea. In the middle of summer with Elsa back at the castle. He might have accidentally started a few rumors about the extent of the queen's magic just then. Fine by him, as long as no more greedy royals set their sights on Arendelle.

The kingdom shifted into celebration mode – complete with ice skating in the middle of summer. _Nice_. He couldn't even do that without pissing off some people.

When the festivities ended and the evening came, he prepared to leave. Elsa seemed content to stay in her kingdom now, and he really wouldn't need to come back, not for winter. At her window, he prepared a design of frost as a message farewell. Or at least, he would have, had she not opened the window with wide eyes.

"Who are you? _How did you do that_?"

Well, shit.

Elsa stared at him, eyes darting everywhere – his hair, his hands, they lingered on his feet – oh right, they were on the second story weren't they and he was in the air.

What the hell was he supposed to say? Oh wait, she asked who he was.

"I… I'm Jack Frost. Nice to… meet you?"

There was a flash of _something_ in her eyes before Elsa gave a nod, the small gesture befitting royalty. "I am Queen Elsa of Arendelle." Her expression flickered for a moment. "My mother once told me about a Jack Frost."

"Yeah, well… that's me." He laughed weakly. There was a guarded expression on her face, a contrast to how free she had been just moments ago. He hovered nervously under her gaze.

He didn't know how to start explaining any of this, especially with so many gaps in his own history. So, he began with hers. "She probably doesn't know it, but we met once, a long time ago. Your mother, I mean. I was just bringing in the winter, and she was sitting there. With you. Sort of. You weren't born yet."

She listened to his story carefully, with only a few questions here and there. "…I see. I suppose you're the reason I have these powers then," she said finally.

He winced, awaiting judgment.

"…Thank you."

Wait, _what_?

Elsa smiled a little at the expression on his face. "There were… so many times I wished I didn't have these powers. I would have screamed at you if you told me this just a day ago. But… they're a part of me. I just forgot how much joy they can bring. So… thank you."

He couldn't even look at her now, the mixture of guilt and relief and everything else rushing through him. "I'm sorry. I'm so sorry."

"…You should come to Arendelle more often. It's tough being by yourself. I would know." Of course she would know, he thought bitterly. She was locked up for so long, whether by her hand or others, because of his mistake.

Her hand covered his clenched fist. It was warm.

There was a smile on her face when he flinched and looked up. "I'd like to be friends, Jack. If that's all right with you," Elsa said kindly.

Slowly, he smiled back.

He should definitely visit more often.


	2. Chapter 2

**AN:** Update! Decided to continue this story, haha. Let's see where this goes, yes?

* * *

It was a strained friendship at first…

...largely because Elsa was the only one that could see him. He'd have to ask about that later. For now, Jack had to stand by as moral support while the queen patiently and politely explained to her dear sister that her new imaginary friend was quite real.

"…No, Anna, I am not having another nervous breakdown. And no, I'm not going to send Arendelle into another off-season winter."

Anna seemed torn between wanting to believe her sister's words and worrying that the strain of the past few days was taking its toll in a new way. It was only when Kristoff mentioned trolls – funny, he hadn't seen trolls in years – that Anna calmed down a bit.

Facing the entirely opposite direction, Anna gave her best curtsy and introduced herself to Jack.

He snickered.

Incidentally, Olaf wandered by and stared. "Hey! Who's the floating guy next to Elsa? Anna, what are you doing?"

On his end, Jack stared back. "A talking snowman…?"

With a hint of surprise, Elsa said, "Didn't you see the one I had guarding the castle? He's harder to miss that little Olaf here." The queen gave an affectionate smile at the beaming snowman.

"I… I don't think he was moving when I dropped by."

With a curious look, he kneeled down next to Olaf. "Hey. Nice to meet you. I'm Jack Frost. I, uh, sorta gave Elsa her powers." And she was certainly going over new leaps and bounds with them. He'd have to try his hand at that. A snowman army sounded pretty cool – _wow, _now _that_ was a terrible and unintended pun. He brushed off ideas of mock battles between Sandy's creatures and snowmen for later.

Olaf took this news with a delighted laugh and rushed over to hug Jack. There was a sharp gasp behind him, followed by, "_Oh my gosh_, he's real! And _cute_!"

And suddenly Kristoff could see him as well, and Jack was suddenly glad he wasn't entirely alive. Manually moving ice must really build some muscle, he thought as he inched away from the other man.

Still, there was warmth in his chest that hadn't been there in years, and he gave Elsa a grateful smile.

* * *

Sometimes, it was really hard getting Elsa to open up.

He could understand it, of course. He rarely said much of substance during encounters with the Bunny, even when it was a precious opportunity to actually talk to someone. Habits were hard to break, and she seemed to have a limit to how much social interactions she could handle. Even with the encouragement of her sister, Elsa retreated back to her room every so often.

So he made it a game.

How long could he go undetected in her room when she had one of her moods?

The first time he tried this, she had been so engrossed in her thoughts that it took a whole hour. The shock and outrage on her face had been hilariously memorable. The resulting punch was just painful.

After the second and third, she seemed to resign herself, half-heartedly glaring at him when she finally found him lounging on the ceiling. It was only during the sixth that she quietly, but firmly asked him to leave upon arriving in her room. At the seventh, he cautiously entered and was greeted with a wry smile.

From then on, she seemed to notice his presence without trying or minding.

It was nice.

* * *

Sometimes, it was really hard keeping up with Anna.

She could blast off a dozen questions in a second, chattering away with an energy that seemed to embody the sun. With genuine interest, mixed in with concern for her sister and him, the princess tried to uncover the mystery of his past without being invasive. Her optimistic enthusiasm was contagious.

No wonder Elsa loved her sister so dearly.

It was interesting to see the stark differences between the two, especially since both took after their mother in appearance. When he mentioned the likeness as a compliment, Anna fidgeted in her seat before murmuring a quiet thank you.

It was only then that he found out the woman had died some years ago along with her husband, answering some of his own questions about Elsa's imprisonment. With a remorseful grimace, he wondered if it had hurt Elsa when he talked of her so casually earlier.

"I'm sorry…"

"It's okay, Jack. You didn't know. And it's nice to talk about mom. Elsa and I… never really talked about them after..." With a pained expression, she excused herself to find Kristoff for an imaginary errand.

Ah, shit.

He hoped Kristoff didn't try to gang up on him with his reindeer.

Not that he would be able to do any real harm – probably, though the guy _was_ friends with trolls - but he didn't want to cause strained tensions between the few people that could see him. Not unless it was the result of a snowball war, at the very least.

Actually, he'd have to try that. Anna mentioned his keen love of ice. He could probably butter up the man with a few creations of frost before pelting him with a barrage of snow. Shaking his head, he drifted off to find Elsa.

He found her by the balcony, looking over her kingdom with a pensive look.

"Jack, will I… become like you? A spirit to bring winter?" she asked quietly.

Shit.

How many times had he asked that himself? Part of him wanted to say yes, for it to be true – humans only lived so long, and it didn't take long for them to forget… And yet, Elsa had already tasted loneliness, self-inflicted out of fear and concern, making it all the more tragic. He wouldn't want her to have his life. She was a queen like her mother. To be loved by her people and raise her own princes and princesses and whatever it was that royalty did. And there were already so many lost years with Anna.

But what if she did?

He honestly didn't know. His own origins were a mystery. Though he'd certainly never heard of the other beings like him… affecting… humans in this way.

"…I don't know."

Elsa gave a small hum. "I thought so…"

They stood quietly next to each other before she bid him good night.

* * *

In late summer, Jack discovered that Kristoff was pretty good at snowball fights. This was to be expected from a man that worked with ice for a living.

Then again, his occupation could be described that way, too. It was kind of funny.

Kristoff and Anna made quite a pair, both on and off the snowball battlefield. But more than not, the teams were comprised of the sisters versus Jack and Kristoff (and occasionally Sven). Having both Elsa and Jack led to a bit of a disadvantage for the other team, after all. Olaf was scorekeeper to the best of his ability until the children of the kingdom discovered the snow, leading to a crazed free-for-all.

He loved it.

* * *

Jack stayed until it was time to make his rounds again.

By now, the whole kingdom was aware of his presence, thinking of him as some sort of minor deity that blessed their queen. It wasn't exactly false, but the reverence that they aimed at him made him uncomfortable at times. Luckily, it wasn't long before his usual mischief in the snow turned it into exasperated affection.

Reputations aside, Arendelle was now home.

But he had a job to do, as he always did. With a rakish grin and expecting a mild scolding, he teased, "Don't miss me too much, your highness."

Elsa met his gaze and smiled, but it was marred with anxiety. The grin faded. "Hey. I'll be back. I promise. Can't keep me away that easily." _Please don't look at me like that._

That worried smile lingered, but she accepted the promise.

And he was off.


	3. Chapter 3

Taking a deep breath, Jack grabbed onto the wind with a shout. Cold air swirled past as he glided by snowy mountaintops, gaining momentum with his cloak billowing behind him. He missed this, having stayed largely grounded (however voluntarily) for the past few months.

Though that summer at Arendelle was the best he had in ages – _the start of many more, he hoped_ - there was something endlessly amazing about flying free in the beginnings of winter. Ever since the last leaves of autumn had started falling, he had been growing restless. There was anticipation from the winds, and Jack tightened his grip.

With a round of theatrics that would have left Elsa rolling her eyes, he created a huge burst of frost, letting the winds scatter it throughout the region. He circled the skies for a good while, indulging in designs inspired by his newfound home. Fluttering wings and reindeer danced away into the forests below, leaving trails of ice.

He always did like to start in the woods.

Diving down and flitting through the trees, Jack appreciated the solitude for once. Though he still preferred the streets of Arendelle with its people and the noise, he now had that contrast to give a new light to the quiet woods. He could appreciate the cool quiet when there was a warm home waiting.

…This lasted for a good five minutes. Silently wandering like a magical elf in the woods wasn't quite his thing, he supposed. Not that they were all that quiet, jingling and all that.

Gripping his hand on his staff, Jack took to the skies again, itching to find another kingdom, a city, anything really. Weselton proved to be a good warm up, and he made sure to add a few extra layers of snow on what he hoped was the Duke's property. Snickering, he passed through the area into a village.

He wouldn't let it hurt as much as before, being a specter to everyone else's fun. With a glint in his eyes, he drew together a snowball, aiming at an unsuspecting child with a blue hat. He could almost see it, the ensuing chaos and beginnings of a playful battle.

Then the strangest thing happened.

"Hey, it's Jack Frost! He's here from Arendelle!"

And suddenly, a crowd of wide-eyed children had surrounded him, pinning him in place with their stares. His element of surprise was gone, and this had never happened before… not before Arendelle, at least. Absently, he noted one child whispering about a Jack of Arendelle to her companion.

With a sheepish grin that turned playful, Jack adjusted his stance and shouted, "Who's ready for a snowball fight?!"

The childish shouts of delight were music to his ears, and he soon orchestrated a battle of epic proportions between several eight-year-olds and one particularly excited seven-year-old. It wasn't until the day turned dark that he realized he was shaking, tremors in his hand that he disguised by holding onto his trusty walking stick. This village wasn't too far off from Elsa's kingdom, but he hadn't expected much recognition beyond its borders. He supposed humans were better at spreading gossip than myth.

Jack of Arendelle.

With an expression more suited to wandering in the woods, he set off into the evening sky.

* * *

Back in Arendelle, Anna slyly asked her sister if she was lonely.

For her troubles, she received a face full of snow and quiet laughter.

* * *

Belief, Jack decided, was a peculiar thing.

It was the lack of it that deprived him of real company for so long. Now he had it, and it was wonderful to be seen, acknowledged, and occasionally shouted at. But what if everyone believed he was something he wasn't? He was… comfortable with Jack Frost, the name that became one of his first memories, the strange spirit that apparently existed to aid winter.

Jack of Arendelle was an equally good name, and he would most certainly be going back once spring started to thaw out the winter. But would that change anything? As he wandered farther away from Arendelle, this was the name he heard more often in whispers. In another village, he heard a garbled tale that presented his two names as different people.

He pondered this as he eavesdropped on a pair of teenage girls gushing about the supposed romance between him and Elsa. Other details fluttered into the conversation - Anna, Hans, a brief mention of Kristoff – but the story was only… somewhat… related to the summer's storm. Whoever their source of information was, they were terribly off. He hadn't even properly spoken to Elsa until _after_ everything had been settled.

"…and then he swooped in with a kiss, an act of true love!" Between the delighted giggling, they were painting a picture of the sort of knight in shining armor that Hans had pretended to be, and he wasn't sure he liked it.

The conversation became more hushed. His ears turned red. Now that _definitely_ didn't-

He almost dropped his stick as he left.

* * *

Elsa wandered down the halls, wondering if she should apologize for yesterday's behavior.

She had been doing so well lately, gaining better control over her emotions in the past few months. Leaving the gates open and letting people in, both literally and figuratively, was good and all, but there was still a level of decorum a queen had to maintain. And yet, she had unceremoniously thrown a snowball into her sister's face. It hadn't even been in the midst of a proper snowball fight. Instead, it had ended dinner.

Her cheeks reddened again, remembering the knowing look on Anna's face.

Absently running her hand against the wall, Elsa wondered if she should send a chaperone on her sister's excursions with Kristoff. It took her a few minutes to realize she was creating unintentional patterns on the walls with ice. With a start, she stared at her work, trying to suppress the instinctual panic. Old habits were always hard to break… And though they never said anything, the servants were probably growing tired of cleaning up the indoor puddles. She could do this.

She thought of Anna, of their childhood and summer's warmth. The frost gleamed brightly before receding, and a wave of quiet relief passed through.

The queen wondered if Jack ever had to melt his creations and added that inquiry to a growing list. Funny how she couldn't think of anything while he had been here, and now that he was away… She wondered if he was getting lonely.

"Elsa! There you are."

With a nervous energy that hadn't been seen since the coronation, Anna shuffled over to her sister. "I'm sorry. I shouldn't have teased. I know you probably miss Jack, I mean, I miss him, too. I even heard Kristoff singing with Sven about it. Snowball was a little unexpected, but hey, it was like a dinner and a show, huh? Haha…"

With an apologetic smile, Elsa replied, "No, I shouldn't have done that. It was uncalled for. I'm sorry as well, Anna."

"Oh. Good. Glad you're not mad." Linking her arm with her sister's, Anna continued, "Now that that's out of the way… Do you think we could have another party? It feels like it's about time for another one, don't you think? We could have warm soup, roast beef, more chocolate…" They walked down the halls, with Anna rambling on various party details. Elsa wasn't sure what brought this on, but she wasn't adverse to another party. It would probably be good for public morale to have another one, considering how the last had ended.

"Also, Kristoff and I would like to get engaged."

Elsa stopped walking.

Wincing, Anna quickly chattered away again, as if to delay a response. "Don't worry! Just engaged! Not married. Not a wedding reception. Just an engagement party. A party to announce our engagement. Kristoff thought maybe a spring wedding would be better anyways, with flowers and not too hot, but more on that later. Though, if it'd help, a fall wedding might also be nice, and we don't mind a long engagement. It's just, it has been months now, and I just thought… It'd be nice to make it… official? With your blessing…?"

The princess finally paused, waiting for her sister to reply.

Well, Kristoff _had_ consistently proved his affections and loyalties over the past few months. They were on amiable terms with one another, even if Anna still seemed rather young to think about getting married. Her advisors hadn't even started pressuring her about the idea of it yet, and she was older. Still, he made Anna happy, and he was taking his title as Royal Ice Master and Deliverer seriously. And Anna did mention a long engagement would be fine…

She would give her blessing. Of course, she would. A part of her was against the idea of… losing her sister, but the feeling was rather irrational. Anna didn't seem inclined to leaving the kingdom, and Kristoff's home and work was also in Arendelle.

"Yes," Elsa said simply.

Anna gave a sound of delight and excitement before embracing her sister. "Oh, thank you, thank you!" With renewed energy, the conversation went back to party planning details, with a particular mention to dress shopping together as sisters. It sounded lovely, and Elsa smiled indulgently.

"We've never really gone shopping together. The seamstress was always makes such pretty dresses and that ice dress you always wear is great, but shopping! Walking through town! Together! We should have done this kind of thing _ages_ ago!"

Briefly, Elsa wondered if Jack would back in time for the party.

The thought was put away for later as she listened to Anna's ideas on ice sculptures as centerpieces.


End file.
